1. Field of the Invention
The present invention relates to an image-taking apparatus which is provided with an imaging device and which forms a subject image on the imaging device to generate an image signal.
2. Description of the Related Art
With the advent of a blue light-emitting diode, it has become possible to generate white light with a light-emitting diode, and it is attempted to replace an incandescent lamp which consumes a lot of power with an LED which consumes a little power, in consideration of future reduction of power consumption. This trend is also spreading in the field of digital camera, and the attempt to apply the LED instead of a xenon tube which has been used for fill light is increasingly active.
The LED for fill light is driven by a high current and is easily heated. Accordingly, there is known a technique for sequentially lighting multiple LEDs within an exposure time to shorten the lighting time of individual LEDs and reduce the load posed thereon (see Japanese Patent Laid-Open No. 2001-215579).
High image quality is required from a digital camera, and it is also required to optimize the amount of fill light which has influence on image quality. There is such a digital camera that fill light is composed of pre-emitted light and actually emitted light in order to optimize the amount of light. In this digital camera, it is possible to perform pre-emission and calculate an appropriate amount of light to be emitted at actual emission, based on the amount of light reflected from a subject. However, such a digital camera which performs pre-emission separately from actual emission has a problem of increase in power consumption separately from the problem of the load posed on the LED described above.
In consideration of the above situation, the present invention provides an image-taking apparatus which prevents increase in power consumption.